What is the minimum value for transmit interval?

I am working with Digi XBee ZigBee S2C module with latest FW 0x405E.
When I am sending TX request very rapidly with interval 0.01 - 1 seconds I get Transmit Status message with status 0x72 (Unknown). It is not documented in the User Guide, I got definition from XCTU XBee API Frames interpreter.

Of course, If I send the same TX request once, or with much larger interval (> 5-10 seconds) there is no problem and I get successful transmission.

I understand that rapid sending of messages is not standard use of ZigBee protocol and Digi modules. But for general understanding what is the reasonable minimum interval for sending TX requests? Maybe Digi has some standard value which can guarantee proper performance of the module?

What kind of transmission are you sending? Unicast or Broadcast?


For example this one:
7E 00 35 11 01 FF FF FF FF FF FF FF FF 7B 0F 01 01 00 01 C0 FB 00 01 E1 E9 83 DC 64 8F 50 38 47 41 72 1D 68 E8 85 83 32 88 CA 84 25 E3 07 08 8A 5B 2F C5 C0 B5 31 19 38 AA

In response I get in one case (failure):
7E 00 07 8B 01 26 15 00 72 00 C6

in other case (success):
7E 00 07 8B 01 7B 0F 00 00 00 E9

That is a Broadcast packet that is being sent to a known 16 bit address. A rout discovery may be required or it will be sent as a broadcast. In either case, you will only be able to send this type of packet once every 5 seconds.

I have doubts that this frame can be classified as broadcast.

XCTU states value 0x000000000000FFFF for 64-bit address as broadcast. In turn documentation states 0xFFFFFFFFFFFFFFFF as unknown address.

So I would say this is unicast with 16-bit addressing with unknown 64-bit address.

That would still require a Rout discovery which you are still limited to once every 5 seconds. Now if you want to send data to a known 64 bit address, then you can stream data up to the number of hops outlined in the manual.

I forgot to mention that it is 1 to 1 network. No need for Route discovery. Which constrains are been applied for this particular case?

Regardless of how many nodes you have, it will still treat each transmission as a mesh as that is what that firmware version does. Perhaps you would be better off installing the 802.15.4 code on these modules instead. After all that is what the 802.15.4 code and standard was designed for. Point to point/multi-point networks.